In Norway there is/were something called dual mono, where the left channel is Swedish and the right channel is Norwegian, one is obviously dubbed. I am thinking that if something similar was the case, like a second or third audio track this could have been embedded in a DTV stream.

I wonder if there was a special Videoway gaming analog channel where the box muted the audio and played some gaming tune while loading the games like you describe. That would have worked but doesn't apply to the patent that was referred.